1. Field of the Invention
The present invention relates to a printed wiring board having an element substrate and a differential signal line for inputting a differential signal.
2. Description of the Related Art
Japanese Patent Application Laid-Open No. 2007-296638 discusses a full-line recording head. A plurality of recording element substrates is arranged in a staggered pattern on a printed wiring board of the recording head.
A clock signal (CLK) is a commonly-used signal in the recording element substrates, and one-to-many connection (multi-drop connection) is desired from the viewpoint of wiring space of the printed wiring board. On the other hand, since different signals are used for the recording element substrates as image data signals (DATA), one-to-one connection (Point-to-Point connection) is desired.
Developments for attaining higher frequency and speed of the image data signal and the clock signal are in progress to attain a high speed recording operation and high image quality. Therefore, it is necessary to keep a stub (branch wiring) as short as possible to ensure good waveform quality when performing the one-to-many connection (multi-drop connection) in wiring of signal lines.
However, in the state where the recording element substrates are arranged in a staggered pattern, a length of the stub is increased. Therefore, since effective characteristic impedance of the signal line is reduced, signal reflection tends to occur, and an amplitude of each of the signals is reduced, resulting in deterioration of signal waveform quality.